RIM and Motorola reportedly hope to break the deadlock over the design of future SIM cards by offering a blueprint that'll either appease every party or alienate all sides equally.

At issue is the shape and size of the standard next-generation SIM: Apple and a band of network operators want a tray-requiring shape and contacts that would permit a convertor for backwards compatibility with chunkier old SIMs. Nokia, Motorola and RIM have pushed for a new contact pattern and a notched SIM for clunk-click, and tray-less, insertion.

The new proposal, apparently put forward by RIM and Motorola, is a compromise but it hasn't secured backing from either of the most-belligerent parties - yet. Copies of the design, as well as Moto's presentation in March that compared the competing interfaces, have been seen by the chaps at The Verge.

What all parties agree on is that a smaller SIM is needed: the first SIMs were the same size as credit cards (conforming to ISO7816), while the second form factor (2FF) is the SIM with which most of us are familiar (conforming to GSM 11.11). Next was the microSIM (3FF), popularised by Apple's adoption in the iPhone; the 3FF just trims off the excess plastic while maintaining the contact pattern.

The undecided 4FF standard (dubbed the nanoSIM) will be thinner as well as smaller, and almost certainly feature a different contact pattern to make that practical, although how different is part of the ongoing debate.

Some might feel the microSIM is quite small enough, but as iFixit's breakdown of the iPhone 4 shows, the SIM is now taking up the same space as the main processor. Get rid of the SIM and you can fit another chip in there:

The silver block to the left of the A4 chip is where the microSIM goes

The Apple-backed 4FF proposal was for a contact-compatible SIM with smooth sides necessitating an insertion tray, while Nokia wanted the contacts shifted to the far end and a notch along the side for easy push-to-lock fitting. The new RIM-Moto proposal, if genuine, places the contacts in compatible locations while maintaining the Nokia notch, appeasing both parties or perhaps annoying them both equally.

There have been claims that Nokia is just trying to protect its patent income, fanned by Apple's offer to waive its own IP fees if its proposal were adopted. That's something of a red herring as Apple's hasn't much IP in this area and Nokia's patents cover much more than the physical shape of the SIM so its revenue is pretty much assured.

Not that Nokia has helped itself by threatening to deny patent licences if its own proposal isn't adopted, claiming that Apple's divergence from rules laid down by telecoms standards body ETSI relives Nokia of its FRAND commitment to licence its technology on a fair and reasonable basis.

The next ETSI meeting isn't until the end of the month, in Osaka, Japan, but rather than having to choose between the two competing camps it seems there will be three options on the table. It remains to be seen if that makes things easier or just divides opinion further. ®